September feature photo

Halong Bay Weather in September

Last updated on
March 29, 2024

The best months to visit Halong Bay are from October to December but what if you only have free time to travel in September? Are you worried about whether the weather is favorable enough to explore the bay?

The following article will provide all the necessary information to help you decide on your Halong Bay trip.

In short:

  • September is one of the best months for its perfect weather
  • Marks the beginning of Halong Bay autumn – the most beautiful season in Northern Vietnam
  • Cancellation rarely happens in September as the typhoon season has come to an end
  • Low chance of bad weather with no more intensely hot weather

Is September a good time to visit Halong Bay?

There are two things to bear in mind about this month of the year: it is autumn and is still in the rainy season. So we can consider that September is a transition from the rainy season – summer to the dry season – fall.

The autumn in Vietnam brings along cooler breezes and more comfortable weather than in the summer. The leaves start changing color before falling, creating a very distinctive natural scenery. Generally, the weather is hot during the day but cools off a bit during nighttime.

Meanwhile, during the rainy season, especially from July to September, visitors are met with daily downpours and even storms and typhoons, especially in July and August.

Many people hesitate to book a trip to Halong Bay during this time of the year for fear of frequent rainfall and the risk of tour cancellation due to typhoons.

That is a valid concern but there are two worth-noting points: (1) it does rain quite frequently but also does not last long: just about 1-2 hours each time and (2) tour cancellation is quite rare.

There are fewer occasions of very stormy weather and typhoons compared to the two previous months. After all, the weather itself is very unpredictable, even in the peak travel season of Halong.

This can be a hit-or-miss experience but how about being spontaneous and daring on an adventure?  


The temperature in September is still very high but no longer blazingly hot and stuffy like other months of summer. While the highest temperature can reach 35-40°C, the average temperature is around 28°C. At night, the temperature can drop to 25°C.

The average number of sunshine hours is 6 hours.

Rainfall & Humidity

September is still a wet month. While there are fewer daily downpours in September compared to July and August, frequent rain showers and even typhoons remain. On average, there are about 16 rainy days. The monthly rainfall is 190 mm, much less than the previous month with an average monthly rainfall of 265 mm.

Visitors can expect an average humidity level of around 72%, which is a slight drop from summer.  As a result, it is more comfortable to take part in outdoor activities.

Sea temperature

The sea water temperature also cools down considerably compared to the previous month so it is comfortable to swim. The average sea temperature is 27°C. The heat this month is not too intense like it is in the summer, and not too cold to swim.

Summary of Halong Bay weather in September

TemperatureAverage: 28°C
Lowest: 25°C
Highest: 35°C
Sunshine hours/day6 hours
Average precipitation190mm
Number of rainy days16
Humidity level72%
Sea temperature27°C

Pros and Cons of traveling to Halong Bay in September


  • Good deals and promotions: Normally in September, there will be fewer local tourists as it is the start of a new school year. Travel and cruise companies offer excellent deals and promotions to attract tourists so you can enjoy the same luxuries at a much lower price.
  • With the lower volume of visitors than usual, you may get even better services and the place becomes more peaceful.
  • Splendid scenery: Halong is very beautiful all year round but its scenery is even more breathtaking during the fall with a crystal clear blue sky and seawater.
  • You should consider booking a cruise and spending at least a night there to immerse yourself in the ethereal beauty of sunset and sunrise along with the light breeze of fall. Better yet, hop on a seaplane and have an astonishing bird’s eye view of this natural wonder. This can serve as an excellent background for wedding or honeymoon pictures.
  • Comfortable weather for outdoor activities: If you are keen on swimming and other activities in the water, traveling in September suits you just fine. You can try snorkeling, kayaking, and visiting floating villages. This is also a good time to catch squids, have them cooked for you on your cruise, and enjoy them with cool beer at night.


  • Possibility of rain, however, it does not rain too much and frequently
  • Cruise may be canceled due to bad weather but a very rare chance

Tips for traveling to Halong Bay in September

Booking tips:

  • Avoid booking around the national holiday (Independence Day – September 2), since the overcrowding situation of people traveling
  • Check for the weather forecast and contact us for an update about your trip in case of bad weather like occasional storms and heavy rain

Packing tips:

  • Bring summer clothes and a light cardigan or jacket
  • Pack your swimsuits for water activities
  • Sunscreen and sunglasses are a must even though the weather is not as intensely hot as in earlier months
  • Bring light raincoats and waterproof bags in case it rains during your trip
  • Pack mosquito repellent during transitional weather and monsoon season

Overall, September is a good time to visit Halong Bay. If you are still concerned about the weather, consider booking your trip from mid-September onward.